A lawn mower in which a cut grass collecting unit (grass bag) for collecting grass cut by a cutter blade is removably attached to the rear part of a cutter housing is proposed for example in JP-UM-A-2-123826. This lawn mower will be described on the basis of FIG. 15.
A lawn mower 230 shown in FIG. 15 has an engine 232 mounted on the top of a cutter housing 231. A cutter blade (not shown) is attached to the output shaft of the engine 232 and rotates inside the cutter housing 231. A grass bag 234 is attached to a rear part of the cutter housing 231.
Grass is cut with the cutter blade. Cut grass is carried through a cut grass carrying passage 235 of the cutter housing 231 into the grass bag 234 by a carrying draft, and is collected in the grass bag 234.
However, there has been the problem that, when cut grass is collected in the grass bag 234 through the cut grass carrying passage 235, as the grass cuttings accumulate in the grass bag 234, the internal pressure of the grass bag 234 increases and obstructs the flow of the carrying draft.
Because of this, it has not been possible to pack enough cut grass into the grass bag 234, and when the volume of the grass bag 234 is increased to increase the volume of grass cuttings that it can hold, there has been the shortcoming that the lawn mower including the grass bag 234 becomes large.
Accordingly, a lawn mower has been awaited with which it is possible to collect as much cut grass as possible in a grass bag of a fixed size.